1. Field of the Invention
The present invention relates to a method and system of relaying data. More particularly, the present invention relates to a method and system in which a source, a relay, and a destination in a relay network jointly use a convolutional turbo code, and thus data relay capability may be improved.
2. Description of Related Art
A relay network facilitates a smooth communication of a shadow region and extends cell coverage. A communication performance between a base station and a mobile station may be improved by cooperation with a relay. A source refers to a transmitting station, the relay refers to a relay station and a destination refers to a destination station.
FIG. 1 is a diagram illustrating an example of a configuration of a relay system according to conventional art.
As illustrated in FIG. 1, the relay system according to the conventional art transmits data from a source 100 to a destination 110 via a relay 120 by using a recursive systematic convolutional code. A data transmission in the relay system, according to the conventional art, may be performed in two separated time slots.
In a first time slot, an information bit of the data is convolutionally encoded in a convolutional encoder, and the convolutionally encoded information bit is transmitted from the source to the relay and the destination. In a second time slot, the data is restored in the relay by using a Viterbi decoder 130, and an information bit is obtained. Specifically, the relay 120 of the relay system according to the conventional art directly performs a decoding operation with respect to the data.
The information bit recovered in the relay is re-encoded in the convolutional encoder via an interleaver 140, and only a parity bit is transmitted to the destination.
A single convolutional turbo codeword comprises an information bit of the recursive systematic convolutional code received from the source 100 in the destination 110, and a parity bit received from the relay 120. Accordingly, a desirable information bit may be obtained in the destination via a turbo decoder 150.
However, a decode error may occur in the relay system according to the conventional art while recovering the data in the relay. Also, the decode error may be continuously transmitted to another communication node by the recursive systematic convolutional code.
Thus, a new relay system which may omit a re-encoding process by using convolutional turbo code in the source and the relay, and increase a coding gain is highly required.
Further, there is a need for an improved system and method of relaying data which recovers a turbo codeword instead of recovering/re-encoding the data in a relay to ultimately prevent an error which occurs in the data recovery process from being transmitted to another communication node.